Food warming hotplates are commonly used in Jewish Orthodox homes to keep pre-cooked food warm because Jewish law forbids cooking on the Jewish Sabbath and on certain festivals. Orthodox Jewish observance does not allow manually turning on and off electric appliances on certain days. Orthodox Jewish observance requires electric appliances to either be on a timer or left plugged in and operating for a minimum of 26 hours straight every week on the Jewish Sabbath. It is a practice to pre-cook food and use a food warming plate to be able to serve warm dishes on these special days.
Therefore, it is desirable to have a hotplate designed to be safely used in homes and operated safely for days at a time every week for years of use. However, there are limited devices in the market today that can safely heat food and safely operate for a minimum of 26 hours straight every week.
Hotplates on the market that are sold typically suffer from thermal degradation and failure when they are used repetitively, continuously, for long periods of time for years. The kind most commonly sold has a live electric wire coil for a heating element surrounded by easily breakable ceramic insulators. This type of heating element arrangement saves on manufacturing costs but has common insulator breakage and electrical shorts to the casing. For example, a frayed and/or damaged cord with an exposed live wire is extremely hazardous and can lead to electrocution or electric fires.
Further, because hotplates on the market are not typically designed to be operated safely for a minimum of 26 hours straight, the bottom of current hotplates will eventually transfer heat to and melt/damage whatever surface the hotplate rests upon if the hotplate is run for a minimum of 26 hours straight.
Further, Jewish Kosher laws require different cooking appliances/utensils for different types of food that must be separated. This can be a problem with typical hotplates as the area that touches the food is not separable from the electronics, and hotplates cannot reach and maintain the temperature of the section of the hotplate that touches the food in order to Kosher the hotplate.
For example, under Jewish Kosher laws, if one were to want to switch from using their oven to cook dairy to using their oven to cook meat, then the oven would need to be koshered by using a self-cleaning function. If the oven does not have a self-cleaning function, but does have a continuous-clean function, one could then cook meat in the same oven if they use the continuous clean mechanism (around 450°) for several hours and then turn the oven to its highest setting, for example 550°, for forty minutes. With older ovens without self-cleaning or continuous-clean functions, a blowtorch may be used to reach the required temperature to kosher the oven.
Thus, under Jewish Kosher law one would typically need a separate hotplate for heating dairy and a separate hotplate for heating meat because hotplates do not have self-cleaning functions or continuous clean functions, and it is not safe to expose the hotplate to blow torch.
Further, according to Jewish law, an electrical circuit may not be closed or opened by any action done by user on Sabbath. Some hotplates have only an on and off setting; however, some hotplates have thermo fuses which can cause the circuit for the heating element of the hotplate to open or close based on changes in temperature on the heating surface. Hotplates without a thermo fuse do not allow for automatic manipulation of the temperature of the heating surface. However, hotplates with a thermo fuse can cause a user to cause the heating element's circuit to close by placing cold food on the heating surface.
Therefore, it is desirable to provide an apparatus for safely warming food which addresses the above-identified problems and provides a way for a person to safely heat up food during a period of at least 26 hours every week without needing to turn on or off any electric appliances.